free database for java

Hello.

I am looking for best free database for java & navigator tool
(Till I found someone to invest on my software ...)

After I have asked some people :
I have found Derby db & Squirrel-sql db-navigator.

.... but I see some opinions that Derby is not supported,
and BTW I didn't understand how I can use major DB that many clients can 
connect it
(I think this is ClientDriver is for that, but I didn't figure out how to 
start the db outside, since I don't know how can I link to the 
system-directory,
 so I assume that may be more then one configuration file in Eclipse and 
also in squirrel-sql, but I didn't figure out where this configuration
file, 
and how can I use it).

I am at the beginning of learning of some Sql's tools (not learning sql,
but 
the tools, since I have got the experience on SQL), so I may give up Derby

for my use.

I need also Hebrew support on the DB, and good tool like TOAD.

My application also need some reports on the future ...

Help me decide, please.

Thanks :)